Saturday, December 31, 2011

The following videos show the progression of the 2011 hurricane season (in 4.5 minutes) and the 2011 tornado season (in 1 minute):

Remember all of those snowstorms in Oklahoma at the beginning of the year? This 34 second video shows the snow piling up over a 22-hour period in Tulsa, OK on February 1st. A record 11-21 inches of snow fell across the Tulsa metro area on that date:

...and on that note - Happy New Year's Eve! I can't wait to see what the world of weather will bring us in 2012!

The outbreak produced in excess of 350 tornadoes (see table below) and took the lives of 321 people. Of those killed, 240 were in Alabama alone. To date, a total of $7.3 billion in insured losses have been paid, with a total damage estimate of $10.2 billion.

Table of tornado outbreak data by state, via Wikipedia

For the duration of this post we'll take a look at the highlights of each day.

Monday, April 25, 2011:

The first day of the outbreak period produced a swath of over 40 tornado reports, extending from northcentral Texas into the mid-Mississippi Valley.

The most significant event of the day took place in Vilonia, Arkansas. Most of the town was completely destroyed by a large tornado that struck shortly after 7:30 pm that evening. Four people were killed and numerous others were injured. Vilonia is located just North of Little Rock.

The picture below was taken just outside of Vilonia at about the time the tornado was taking place. It shows what appears to be a large tornado at least partially obscured by rain:

An image from the Little Rock area doppler radar before the storm struck Vilonia shows a strong tornadic signature on both the reflectivity (rain and hail - left side of image) and velocity (wind speed and direction) images of the radar:

On the same image below, I've noted the location of a "debris ball" in a yellow circle on the reflectivity image and the strong rotational signature in the velocity image with a white circle:

A debris ball is a signature that is indicated when the radar is detecting debris that has been picked up and carried aloft by the tornado. This is typically only observed with very strong and/or violent tornadoes, and when significant damage is being done.

Indeed, the damage in Vilonia was significant, with many homes completely destroyed or very heavily damaged:

Due to the strong signatures on radar, the city had over 30 minutes of warning before the tornado struck. Undoubtedly the death toll would have been higher had that not taken place.

Tuesday, April 26, 2011:

On the next day, April 26, over 52 tornadoes were confirmed (of the 100+ reports received as noted on the map above), in a swath from northeast Texas across the Deep South and middle Tennessee Valley. A few isolated tornadoes also took place in Michigan and New York state.

The strongest tornado that took place on the 26th was of EF-3 intensity, near Fort Campbell, Kentucky. One structure was completely destroyed and several others heavily damaged on the Ft. Campbell Army Airfield, and several barns and homes in the city were also damaged or destroyed.

Unfortunately, the tornado events of the 25th-26th turned out to be only a "preview" of what was to come the following day... which would prove to be the most deadly and widespread tornado day in recent U.S. weather history...

Wednesday, April 27, 2011:

On April 27th, 2011, the most significant tornado outbreak in over 35 years took place across much of the Eastern third of the U.S. Just over 200 tornadoes were confirmed on that day which shattered the old record of 148 twisters during the Super Outbreak of April 3-4, 1974.

The image below shows the preliminary tornado tracks across the South:

The following image illustrates the "killer" tornado paths of that day. A total of just over 300 people were killed by 28 different tornadoes:

Hundreds of tornado warnings were issued from the lower Mississippi Valley into the Northeast on April 27th, a record number for any one day in U.S. weather history. One National Weather Service ("NWS") office alone (Huntsville, AL) issued 92 tornado warnings on that day.

Over 90% of the tornadoes that took place on April 27th did so inside of a Tornado Warning area, and 100% of the tornadoes took place within a Tornado Watch area. These statistics make the staggering death toll of 300+ even harder to accept, at least when applying "conventional wisdom". As it turns out, conventional wisdom isn't a very good barometer to use when it comes to the strongest of tornadoes, especially those of EF-4 and EF-5 intensity that track through heavily populated areas.

As the events one month later in Joplin, MO would further illustrate, seeking shelter above ground, as conventional wisdom would suggest (i.e., in a small interior room on the lowest floor of your home or business), is no match for a high end EF-4 or any EF-5 tornado. A specially designed, below ground tornado shelter or an above ground tornado safe room offer the best chances of survival in these situations.

There were many "stand out" tornadoes that took place on April 27th (11 were of EF-4 intensity and 4 were of EF-5 intensity). The events that took place in Alabama were particularly deadly and damaging. In particular, the tornado that tore a swath of destruction from near Tuscaloosa:

...to Birmingham:

...was on the ground for nearly 81 miles and had a damage path width of 1.5 miles at times. The official NWS survey of the tornado damage path is shown on the following 3 images. The colored triangles along the damage path refer to specific EF-intensity categories: Blue = EF-0, Green = EF-1, Yellow = EF-2, Gold/Brown = EF=3, Red = EF-4:

The supercell thunderstorm that produced the Tuscaloosa to Birmingham tornado was one of the longest lived (if not the longest lived) tornado producing thunderstorms of the day. As you can see by the composite radar image below, the storm tracked from east-central Mississippi into southwestern North Carolina (a distance of over 350 miles) and was producing tornadoes most of the time!

I have made several posts on the blog this year regarding the Tuscaloosa and Birmingham area tornado. You can view those individual posts here:

Another violent tornado, rated EF-5 intensity, tracked to the North of Birmingham on the 27th, impacting the Athens and Huntsville areas (among others in the region):

This particular tornado was on the ground for 107 miles across north Alabama and extreme southeast Tennessee. It produced a damage path up to 1.25 miles wide and killed 72 people.

At least one major good came from the tragedy near Athens, thanks to this photo:

That is the Harrison family - and they were indeed saved by their tornado saferoom on April 27th. You can see that it is literally the only room left standing in their home. That photo and their story received world wide media attention (including here on the Original Weather Blog), and brought the issue of tornado saferooms and sheltering to the forefront of many peoples minds.

It is my hope that their story, as well as the story of Sam from Joplin, MO will lead many to purchase and install a tornado saferoom before the 2012 tornado season gets underway.

The Athens/Hunstville area tornado originated back to the Southwest near Phil Campbell, where several cases of EF-5 damage were observed, in that the foundations of frame built homes were wiped completely clean, as shown in this photo below (near Phil Cambpell):

Another tornado tracked between Birmingham and Huntsville, near Empire, AL on the 27th. This tornado took place in a rural area with no notable damage or injury (thank goodness), but I wanted to point it out and show this video to try and put to rest a widespread myth that tornadoes cannot travel over hills, mountains or other rugged terrain:

As you can see, this particular tornado had no problem with the rugged terrain of the region. Had any homes or buildings been in the way, they would have been heavily damaged and/or destroyed.

While we're still talking about the area just North of Birmingham, another tornado, this one of EF-4 intensity, struck from near Cullman on Northeast to halfway between Huntsville and Albertville. The following YouTube video showing the tornado moving right through Cullman is quite impressive, and is well worth waiting through the 25 second commercial at the beginning:

Here is another view of the Cullman tornado, taken by someone standing out in their front yard:

Watch that video again. If you didn't notice the first time, take a look at the front door and/or yard of each house in the video...

Did you notice that there is a person literally standing outside every one of the houses, looking at and/or taking some type of video of the tornado. Why were they not in their shelters? Granted, in hindsight, we know that the tornado was moving right to left and did not directly threaten this particular location, but did the people standing out there know that at the time? Also, keep in mind that the Tuscaloosa tornado threw debris up to 20 miles away from the actual tornado. An area as close to the tornado as we are seeing in this video would certainly be under a threat of flying debris.

Continuing on with this theme, the next video was shot from the 3rd story balcony of an apartment building. This appears to be the Tuscaloosa tornado but it is not positively identified in the video. Listen closely and you can hear the person taking the video remark about the debris flying in the air overhead, yet he stays out on the balcony filming. You finally hear someone in the background say that it's time to get inside, once it has begun to move away, of course...

Don't get me wrong. I enjoy watching the videos so that we can learn more about tornadoes, etc., but I would much rather watch video taken by a trained spotter or storm chaser that knows exactly what their location is in reference to how the tornado is moving and is safely out of harms way. In other words, "don't try this at home" unless you know exactly what you're doing!

Thursday, April 28, 2011:

The final day of the 4 day outbreak, April 28, 2011, featured 49 confirmed tornadoes, mainly along the Eastern seaboard and the far Southeast:

There were no EF-4 or EF-5 intensity tornadoes on the 28th. There were 3 EF-3 intensity tornadoes, 2 in Georgia (one West of Griffin and one Northwest of Forsyth) and one in Virginia (near Bristol). Unfortunately, each of these 3 stronger tornadoes were killers. There were 2 deaths associated with each of the EF-3 tornadoes in Georgia and 3 deaths associated with the EF-3 tornado near Bristol, Virginia. Each of these stronger tornadoes took place during the pre-dawn hours of the 28th (or late on the 27th, depending on how you want to look at it), which explains their absence from the map above.

The most significant damage of the day was in association with the tornado near Bristol, Virginia (right along the Tennessee/Virginia borders). It caused major damage in the Glade Spring area, including a truck stop that was heavily damaged along I-81 (might want to mute the musical selection - not sure it fits the material - but the photos are impressive):

For a complete tabular listing of each confirmed tornado during the April 25-28 outbreak, I recommend this Wikipedia link.

Thursday, December 29, 2011

Folks in the Eastern third of the nation that have grown rather complacent after the relatively mild winter thus far are in for a surprise to start off the new year. The latest run of the ECMWF model is shown below, valid 7am EST on Tuesday morning, January 3rd. The left half of the image is the middle and upper level depiction of the weather, with the right half being the surface level:

I've drawn in the position of the jet stream (yellow line/arrow) and the surface cold frontal position on the same image below:

If the above model verifies, which it is on track to do, then bitterly cold air will grip much of New England and the Northeast early next week. Sharply colder temperatures are likely over the Southeast as well, including a possible hard freeze well into Northern and possibly even central Florida on Tuesday and/or Wednesday mornings.

It does appear that the cold shot will be relatively brief, with near (to possibly even above) normal temperatures returning to much of the region during the 2nd half of the week.

Especially in a year so full of violent weather at times, words cannot describe how deeply I appreciate my readers, both "regular" and new, of the blog. We're to the point now where thousands of people all around the world visit on an average day!Thanks again, and a very Happy New Year to all!If you have any thoughts or suggestions as to what you'd like to see (more, less or in between) on the blog in 2012, please feel free to comment or send me an e-mail.

Monday, December 26, 2011

With total property and crop losses exceeding $10 billion, the severe drought and heatwave of the spring and summer (and drought continuing into the fall) across the Southern Plains and Southwest U.S. comes in at #2 on the list of billion dollar weather disasters of 2011.

With late winter and early spring rains lacking, the drought was already getting underway across much of Texas and New Mexico by mid-March:

...and would only worsen throughout the summer. By August 30, extreme to exceptional drought conditions were present across much of the southern Plains and southwest U.S.:

Through December 26, 2011, much of central and eastern Texas still faces a rainfall deficit of some 15-20 inches for the year, with much of New Mexico facing a deficit of 6-12 inches (note, the deficit is actually larger in some places that saw below normal values of rainfall toward the end of 2010):

Departure From Normal Rainfall for 1/1/11 - 12/26/11

The extreme drought took a heavy toll on livestock and crops across the South. Not only did ranchers face drought on their own properties, but the widespread nature of the event caused hay and other livestock related feed prices to skyrocket. Add the increased transportation costs to the mix (to bring feed and other resources in from areas that were not experiencing drought), and it put some family ranchers out of the cattle business altogether.

In Texas alone, drought related losses to livestock are estimated at $2.1 billion.

Many may not have realized it, but the drought started to affect the pocketbooks of Americans by late summer and early fall, via increasing costs at the grocery store. In Texas, the peanut crop was particularly hard hit by the drought, which resulted in a dramatic increase in cost in everything from peanut butter to mixed nuts across the country by the fall.

Other crops that took a hit from the hot and dry weather in Texas included wheat (estimated loss of $243 million) and corn (estimated loss of $327 million).

The cotton crop was the hardest hit of all, at an estimated $1.3 billion in Texas alone.

The American Farm Bureau estimated that Thanksgiving dinner cost Americans 13% more to prepare on average this year, compared to 2010 (a similar figure is being cited for your Christmas meal as well). Among other things, beef prices are up 10-15% and poultry prices are up 15-20% on average (compared to one year ago).

Beneficial rains have fallen across much of the Northeastern portions of the region over the last 30 days:

Departure From Normal Rainfall for 12/1/11 - 12/26/11

...however extreme to exceptional drought conditions remain firmly in place across the majority of southern, central and western Texas into New Mexico and Arizona. That trend is forecast to continue so for the foreseeable future:

...which will spell a continuation of further economic losses and strong pressure on food prices into at least the first half of 2012.

Editorial note: The Texas and Southwest U.S. wildfires were not factored into the drought assessment. When tabulating the list of billion dollar weather disasters of 2011, NOAA classified the wildfires separately. With $1 billion in associated property losses so far, the Texas and Southwest wildfires of 2011 currently rank in the #12 spot on the list of billion dollar weather disasters of 2011.

Severe thunderstorms produced very large hail and several tornadoes in the Victoria region, in and near Melbourne, Australia on Christmas Day. The storms struck late in the afternoon. The photo above shows strong rotation within a thunderstorm as it passed near the RAAF Base at Sale (to the East of Melbourne), by mid-evening.

The first sighting of a tornado was reported around 4pm local time near Fiskville, to the West of Melbourne. The corresponding radar image from the Bureau of Meteorology (below) showed a very pronounced hook echo in association with what we here in the U.S. would call a supercell thunderstorm (inside red circle in the upper left quadrant of the image):

Damage was widespread across the region, both from tornadoes and/or damaging winds:

...and very large hail:

Take a look at the size of this monster hailstone captured (in a near one in a million, mid-air shot) by local resident Alan Beattie:

Indeed, I've seen more damage photos from hail across the region than tornadoes or high winds. The photo below shows extensive damage to this gentleman's car (courtesy of the Herald Sun):

The hail was so prevalent across parts of the region that it created a white Christmas for some:

While tornadoes and damaging hail may seem rather odd to us here in the U.S. on Christmas day, it is actually Summer "down under" in Australia right now. A storm of this severity is, however, unusual for Christmas day, even where the season is warmer and more unstable.

A broad area of light snow continues to fall across westcentral and now parts of northwest Texas, where it is mixing at times with freezing rain or drizzle and some sleet. It has also been snowing most of the night across far southeast and part of east-central New Mexico.

A Winter Storm Warning is in effect for the pink shaded areas on the above image today, with a Winter Weather Advisory for the tan shaded areas. The warning includes Roswell, Carlsbad, Hobbs and Odessa. The advisory includes Abilene, Lubbock, Midland, San Angelo and Plainview.

A zoom-in on the Midland area radar shows a swath of light with some occasionally moderate snow across the region:

The latest run of the HRRR high resolution computer forecast model is calling for a swath of 3-4 inch snow with localized amounts of 6-8 inches across southeast New Mexico and into extreme west-central Texas. The image below is the snow accumulation forecast valid at 3pm CST this afternoon:

Light snow is likely to move and/or develop into parts of northwest Texas this afternoon and evening, with a dusting to 1 inch possible in those areas by early Christmas morning, as indicated on the latest run of the GFS model's snow depth forecast valid 6am CST on Christmas morning:

Folks with any travel plans across west-central or northwest Texas into southeast New Mexico should use caution and allow plenty of extra time to reach their destinations.

Meanwhile, out ahead of the wintry weather, widespread drizzle, light rain and showers are breaking out across much of the central and eastern two-thirds of Texas this morning:

Rain will continue to increase in areal coverage throughout the day today and into at least the first half of tonight. Widespread rainfall amounts of one half to one inch are likely through 6am CST on Christmas morning, mainly within the darker green and blue shaded areas on the image below:

As temperatures fall and an upper-level weather disturbance moves over the Hill Country to the West of I-35 tonight, it is possible for some flurries or very light snow to mix with the rain at times after midnight (in the Hill Country), however no accumulation is expected.